Different Aspects of God

When a human being for his own benefit can have so many aspects viz.-son, friend, father, teacher, officer, helper, cleaner, lover, giver, taker, enjoyer, desirer, murderer, thief, police, judge etc., why can't the Supreme God can have different aspects viz-Krishna, Hanuman, Durga, Shiva, Dattatreya, Buddha, Christ, Mohammed etc. for the benefit of His fellow (human) beings?

It is said that, Supreme Lord or Brahman is without any aspects at all and He is ultimately pure and only Truth personified. So if a man can get out of all his self-created aspects, what will be the different between Brahman and Self?